Assembly Sequence Planning Studies For Open-structure Products

Assembly is an important link in production and manufacturing,which is directly related to product quality,performance,life and maintainability.Assembly sequence planning is an important part of assembly process planning,and the quality of sequence directly affects assembly quality.Open structure product is a kind of new product architecture mode which is put forward to adapt to mass personalized production mode.At present,the research on open structure products mainly focuses on the product design stage,and there are few researches on the automatic assembly sequence planning in the assembly process planning stage.Based on the traditional assembly sequence planning theory and combined with the characteristics of open structure products,this paper studies the assembly sequence planning methods and technologies of open structure products.It provides some methods and technical guidance for automatic assembly sequence planning in production enterprises using open structure product architecture pattern.This paper mainly carries out the following aspects of research:(1)In the analysis of the general assembly sequence planning method,based on the analysis of the structure of open product assembly sequence planning requirements,product assembly sequence planning to open structure should be based on the sub assembly based on open structure products sub assembly for assembly sequence planning ideas,and put forward the open architecture of product assembly planning process.(2)The subassembly division method of open structure products is studied:Starting from the features of the open structure of the product itself,based on the division of function a geometric structure hierarchical model,combined with the open structure of the product can replace,update,add or delete features,increased the disassembly and maintenance of the first layer of the criterion,and increases the replaceable,can upgrade as indicators,and then on the basis of the model established classification principles of open structure of sub assembly product,The improved openness formula in this paper is used to determine the types of each subassembly,and the proposed concept of complexity is used to judge whether the sub-assembly is qualified or not.(3)Based on the subassembly division,the assembly sequence of the open structure product was modeled,and constraint matrixes,such as interference matrix and supporting relationship,and assembly tool,were established.Then,the evaluation function was established using constraint indexes.The improved LSA algorithm is used as the main optimization algorithm,and the BAS algorithm is used to improve the LSA algorithm,which is easy to fall into the local optimum and the solution accuracy is not high.(4)Based on the research to the paper folding machine as an example,the assembly sequence planning system using MATLAB,this paper proposed is verified of sub assembly division method and the generation of assembly sequence,the improvement of lightning must search-longicorn hybrid algorithm and the commonly used particle swarm,differential evolution,the comparison between lightning search algorithmThe excellent performance of the hybrid algorithm in assembly sequence planning is verified.